持续负温环境下水泥水化特性试验研究

Experimental study on hydration characteristics of cement paste under sustained minus temperature

研究负温(-3℃)养护条件下不同水灰比水泥净浆在一定龄期内的水化放热量及水化程度变化规律。通过对不同龄期下3种水灰比(0.24,0.31,0.38)水泥净浆水化放热量的计算,分析水泥水化机理和水泥净浆微观结构变化。结果表明:负温(-3℃)养护条件对3种水灰比水泥净浆水化程度有明显的抑制作用;前12 d内水灰比为0.38的水泥净浆的放热量最大,12 d之后水灰比为0.31的水泥净浆的放热量最大,负温环境下存在着该温度范围内的最优水灰比;3种水灰比水泥净浆在前12 d内水化程度增长较大,随着龄期的增加水化程度增长变缓。

The paper takes three samples of neat cement pastes（ at different stages of maintenance age） with different water cement ratios 0. 24,0. 31 and 0. 38 and studies their heat release and the hydration process at a minus temperature of- 3 ℃. In accordance with the heat release calculation,the paper looks into the hydration mechanism and the structural changes that take place at a micro level. The results show that the minus temperature（- 3 ℃ in this case）largely undermines the hydration process of all the specimens. In the first 12 d the specimen with a water cement ratio of0. 38 releases the largest amount of heat,while during the days followed the water cement ratio of 0. 31 surpasses it in this regard. The optimal ratio can be found for this temperature level. The hydration process stands evident in the first 12 d for all the specimens and then fades out as times goes by.